Another wave of COVID is coming

(ORDO NEWS) — About three weeks ago, the number of COVID cases in the UK changed dramatically, prompted by the introduction of a more transmissible sub-variant of Omicron called BA.2. (There is no evidence yet that the new subvariant causes more severe disease.)

The number of cases is growing in Switzerland, and in Greece, and in Monaco, and in Italy, and in France. With BA.2 already present in the United States, The Washington Post reports that epidemiologists and public health leaders suspect North America will be next.

After all, the newspaper writes, “in the past two years, a large-scale outbreak similar to that in Europe was followed by a similar surge in the United States a few weeks later.”

It is true that watching the Delta and Omicron waves in Europe last year was like peering into the crystal ball of the future pandemic in America. Cases in the UK started rising in early June, peaked about a month later, and bottomed out in early August.

In the United States, a surge in cases began in July, peaked in September, and reached a minimum in October.

In the UK, cases started to rise again around December 10 and peaked on January 4, and in the US on December 18 and January 10, respectively. Britain reached its post-micron low at the end of February. If this pattern continues, then we should reach our… right now.

But this correlation does not always hold. If over the past two years some races in European countries were accompanied by races in the US, others simply were not. And the wave that we are now seeing abroad may well be among the latter.

Differences between the U.S. and European countries in variant levels, previous infections, and pandemic control policies could lead our countries’ incidence rates to take a different path. “There are a number of things that separate the American experience from the European one,” Bill Hanage, a Harvard epidemiologist, said at a news conference yesterday.

The fact that Europe is sometimes two steps ahead of us may be due to chance.” The most influential variants – Alpha, Delta and Omicron – were first identified in the UK, India and South Africa, which are more associated with Europe than with the USA.

These variants just arrived in Europe earlier than in the US, but that trend could easily reverse.”If the next option starts in Brazil, it’s much more likely to end up in the US than in Europe,” Graham Medley, an infectious disease modeler, told me. diseases from the London School of Hygiene and Tropical Medicine “We all follow each other.”

Vaccination levels, the type of vaccine used and previous infection patterns may also have influenced the Europe-Americas trend, says Sean Truelow, an epidemiologist at Johns Hopkins University.

For example, the AstraZeneca vaccine, which was widely used in the early stages of vaccine distribution in the UK, does not protect against infections as well as the Pfizer and Moderna vaccines, which have been the most popular in the US since the beginning. “It’s a very complex system, so it’s hard to say exactly,” Trulove told me.

Differences in politics and behavior can also determine trends over time, and at present, politics and behavior in Europe are, let’s say, different. In England, people who test positive for the virus are no longer asked to self-isolate; at the same time, Spain and Italy have only recently lifted the requirement to wear masks outside.

“Restrictions that have been lifted in many European countries include restrictions that have never been in effect in much of the United States,” Khanage said, which could mean that Europeans’ lives have changed faster in recent weeks than Americans’. Overall, the US hasn’t had many COVID restrictions in place since last summer.”

Oddly enough, due to the fact that America has recently taken a light-hearted approach to the pandemic, incidence rates here are easier to predict. Throughout the pandemic, the hardest part of the job of modellers has been accounting for how American politics and behavior will change, says Lauren Ansel Myers, head of the COVID-19 Simulation Consortium at the University of Texas at Austin.

But during the winter, schools mostly didn’t close, and Americans mostly went about their business. Unexpectedly, the predictions made by Myers and her team turned out to be accurate. “We’re not used to being so precise,” she told me.

But this does not mean that modelers are ready to say exactly what will happen next with America. “Over the past two years, we’ve found that models struggle at these critical points of change,” Truelow told me. We won’t know if we’ve entered the trough until it’s over and the infection rates are back up again, he said.

Myers said she expects more accurate forecasts in a week or so. She needs more time to see will plateau or rise in cases in some regions of the US, and get more information about how long people are protected from infection or disease after exposure to omicron She also wants to know more about how easily BA.2 can infect people who survive one of the two sub-options, BA.1 and BA.1.1,

The BA.2 is considered to be slightly more transmissible than the BA.1 and is already in the US. This may sound ominous given what’s going on in Europe, and it could also be an indication that the wave in the US is coming soon, according to the pattern set by Delta and Omicron.

Hanaj assured me that BA.2 would almost certainly beat the other options here too, but that doesn’t mean the US is doomed to the same surge. When the BA.2 arrived in Europe, it became popular almost immediately.

In the US, Hanage says its growth has been much slower, perhaps because it competes with BA.1 and BA.1.1. Even if BA.2 starts to develop strongly tomorrow, it will do so during a much lower trough and likely less favorable weather conditions for viruses than those it experienced when it made its claim to UK dominance.

All of this could mean that BA.2 will have less of an impact here than in Europe. This has happened before: In the last weeks of 2020, the Alpha variant became the cause of the majority of cases in the UK and contributed to a devastating surge.

(Around the same time, the US also experienced a devastating spike in cases, with the highest death rates of the entire pandemic, but Alpha was not a major player; had it been, the winter spike would likely have been even worse.)

Alpha began to dominate the US only in the spring, when the weather became warmer and Americans began to vaccinate. This may help explain why there hasn’t been a big spike in Alpha in the US; if anything, the curve of this period is more like a plateau. “We rather dodged the bullet,” Khanaj said.

If we’re lucky, we may be able to avoid another BA.2 bullet.” Hanage said his best prediction for the next few months is that some regions of the US will continue the downward trend, but at a slower pace. In other areas There is likely to be a spike in cases – wastewater data suggests it could happen soon – but for now, no one can guess the size of those spikes.


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